1. Field of the Invention
The present invention relates generally to devices for cleaning and filtering materials, and more specifically to a relatively small, removable, temporary carburetor cover for short term installation on a carburetor. The present cover includes filtering means therein, so the engine may be run for carburetor tuning and adjustment purposes with the cover in place, to prevent the ingestion of foreign matter (dirt, small parts, etc.).
2. Description of the Related Art
While nearly all motor vehicles used in street operation are equipped with fuel injection systems for better exhaust emissions control, better flexibility under various conditions (cold starting, better fuel distribution, etc.), there are many classes of off-road motor vehicles which still use carburetors, due to the rules governing those various classes.
This is particularly true of motor vehicles used in racing (i.e., race cars of various types), ranging from so-called "hobby stocks" up to racing automobiles used in major league Winston Cup racing. Most racing classes for full-bodied cars, as well as certain classes of open wheel cars which run in various minor league series, are required to use carburetors for their fuel distribution systems, rather than fuel injection.
Air intake filter systems for motor vehicle carburetors are typically secured directly to the mouth of the carburetor, with no intervening intake system. Such filters are generally relatively large in comparison to the carburetor diameter, in order to provide a relatively large filter area to produce a relatively low restriction for air passing through the filter and its housing. Accordingly, the typical filter housings of such carburetors extend well beyond the lateral dimensions of the carburetor.
This is ordinarily not a serious problem, as access to the carburetor is obviously not required while the vehicle is in motion. However, access to the carburetor is required when the engine is being tuned or adjusted, for adjusting fuel/air mixtures, adjusting the point at which the secondary throttles begin to open in multiple barrel carburetors, etc. Many such adjustments may be accomplished while the engine is running, and in fact, it can be quite difficult to accurately accomplish many such adjustments when the engine is shut down. Yet, the conventional air cleaner must be removed from the carburetor for access to the various adjustment points.
This may not be a significant problem under some circumstances, but the removal of the air cleaner from a carburetor while the engine is running in a relatively dirty environment can lead to the ingestion of dirt and other foreign matter into the engine, which is always harmful to the engine and may be disastrous. This is particularly true in many automobile racing environments, particularly on dirt tracks and even at a paved track with a dirt or turf infield area where the cars are being worked on before or between races. The amount of dirt and dust which is kicked up into the air by a number of racing automobiles in such an environment is considerable, and in fact often reaches an extent to which the dust and dirt is quite visible in the air at such tracks during racing events. As an operating engine performs as a pump, drawing air from the atmosphere through the carburetor and into the engine, it will be seen that a considerable amount of dirt and dust may enter a carburetor and engine during the time the engine is running in relatively dirty air.
In addition to the above considerations, racing mechanics are always pressed for time, and it is quite easy under such circumstances to inadvertently drop a small part which may fall into the carburetor throat and thence be ingested into the engine, where it almost always causes considerable damage. Even if the mechanic realizes such a part has been dropped into the carburetor throat, there may be insufficient time to shut down the engine before the part passes into one of the cylinders and causes internal damage to the engine.
Even if the engine is not operating when such foreign matter is dropped into the carburetor, often the engine intake system must be disassembled for recovery of the part. Such disassembly obviously requires additional time, which is seldom available at a race. Accordingly, almost all mechanics will cover the carburetor throat when the air cleaner is removed, in order to preclude the entry of dust and dirt therein and the dropping of any foreign objects into the carburetor throat when the engine is not running.
However, such cover plates do not allow the passage of any air therethrough, and thus cannot be used when the engine is running. The only solution is to keep the conventional, relatively large air cleaner in place, or to remove it for adjustments to the carburetor and hope that no significant amount of dust, dirt, or foreign matter passes through the carburetor during the time the air cleaner is removed.
Accordingly, a need will be seen for a filtered carburetor cover which may be temporarily installed on a carburetor throat when the conventional air cleaner or screen is removed. The present carburetor cover is relatively small and has a diameter substantially the same as, or at least no larger than, the carburetor with which it is used, in order to provide access to the external components of the carburetor for adjusting and tuning while the engine is running. The present carburetor cover includes filter elements in the intake portion thereof, to preclude the ingestion of any significant amount of foreign matter into the engine while it is running.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 2,761,527 issued on Sep. 4, 1956 to John J. Dreznes, titled "Filter Body," describes a relatively large and bulky air filter, resembling the conventional oil bath filter used commonly up to the 1960s. the Dreznes filter includes a fitting for installing over the throat of a carburetor, with the fitting being defined by a clamping ring 41 therearound. The clamping ring has a considerably smaller diameter than the body or housing of the air cleaner, as may be readily seen in FIG. 3 of the drawings of the Dreznes Patent. Accordingly, the sides of a carburetor over which the Dreznes air cleaner is installed, cannot be readily accessed. The present filtered carburetor cover is not intended for use during normal engine operation, but as the name indicates, is a cover with a filter therein for use in tuning and adjustment operations and which provides full access to the external components of the carburetor.
U.S. Pat. No. 5,307,771 issued on May 3, 1994 to Alwin J. Stahel II et al., titled "Motorcycle Air Cleaner," describes an air cleaner assembly having a secondary throttle assembly on one side thereof. The assembly is operated by manifold vacuum from the engine, and is set to open when manifold pressure increases, i.e., when the throttle is opened for increased engine power. This provides a larger intake area to the air filter, thus producing less restriction to the filter for better engine "breathing." As noted further above, this is the reason that conventional air cleaners are relatively large in comparison to the carburetor diameter, i.e., to provide a significantly larger cross sectional area for the air cleaner element in order to compensate at least partially for the restriction of the air cleaner element. The Stahel II et al. air cleaner body extends well beyond the outer dimensions of the carburetor, as can be seen in the cross section of FIG. 2A of the Stahel II et al. Patent. In contrast, the present filtered carburetor cover preferably extends no further than the outer dimensions of the carburetor, in order to allow complete access to the carburetor as required when the filter cover is installed thereon.
U.S. Pat. No. 5,368,621 issued on Nov. 29, 1994 to Stephen R. Pool, titled "Filtering Air Cleaner Cover For Internal Combustion Engine," describes a conventional, relatively large diameter air cleaner in which the impervious top cover has been replaced with an additional filter element. Here again, Pool recognizes the restriction of the typical air cleaner element and the need to provide the greatest practicable inlet area through such air cleaner elements. The air cleaner housing with which Pool uses his filter cover is a relatively large diameter device, as evidenced by the relatively small size of the engine inlet 14b shown in FIG. 1 of the Pool U.S. Patent. The Pool air filter housing thus extends well beyond the dimensions of any carburetor or other intake system to which it is attached, rendering access to adjustment features thereof, impossible while it is installed.
U.S. Pat. No. 5,582,146 issued on Dec. 10, 1996 to Peter Linsbauer et al., titled "Suction Air Filter," describes a filter for an internal combustion engine, with the filter including multiple air cleaner elements in series therein. The Linsbauer et al. filter is not intended for maximum power production, as can be seen from the multiple filter elements and their restriction to air flow. The exemplary filter unit is shown installed on an internal combustion engine powered cutoff saw, which obviously produces a considerable amount of debris when in use, hence the need for optimum air filtration as opposed to maximum power. Accordingly, the filter housing 3 has a considerably larger diameter than the carburetor 1, as is clearly shown in FIG. 2 of the Linsbauer et al. U.S. Patent. Accordingly, access to the external adjustment components of a carburetor to which the Linsbauer et al. filter assembly is secured, is extremely difficult, if not impossible.
U.S. Pat. No. 5,688,299 issued on Nov. 18, 1997 to Thomas I. Goodwin, titled "Air Filters," describes a low, generally cylindrical filter having side and top filter elements. The top element precludes access to the conventional central filter housing attachment bolt. Accordingly, Goodwin provides for removal and installation of his filter by means of quick release fasteners (e.g., Dzus; tm, Camloc; tm, etc.), as used in the aviation industry. Goodwin recognizes the importance of the largest possible filter area for reducing air flow restriction as much as possible; hence, the top filter element in addition to the side element. The Goodwin filter is thus more closely related to the filter disclosed in the U.S. Patent '621 to Pool, than to the present filter cover invention. Accordingly, the Goodwin filter has a considerably larger diameter than the carburetor to which it is secured, as shown clearly in FIG. 2 of the Goodwin U.S. Patent. This renders any carburetor adjustments extremely difficult or impossible when the Goodwin filter is installed thereon, due to the inaccessibility of the carburetor due to the overhanging Goodwin filter. The substantially smaller diameter of the present filtered carburetor cover, while not providing the relatively large filter area of conventional filters, provides ready access to the various adjustable components of a carburetor to which the present filter cover is installed.
U.S. Pat. No. 5,706,777 issued on Jan. 13, 1998 to Helmut Schlessmann et al., titled "Suction Air Filter For A Combustion Engine With Diaphragm Carburetor," describes a generally conventional filter housing with a foam filter therein. The housing includes a bypass tube for compensating for decreased manifold pressure due to increased restriction of the filter element in the event the filter element becomes substantially clogged. The single drawing Figure clearly shows the filter housing as having a substantially larger diameter than the carburetor to which the housing is attached, unlike the present filtered carburetor cover. The problems of such a configuration in adjusting a carburetor to which such a filter is attached, and the solution provided by the present filtered carburetor cover, have been described above.
U.S. Pat. No. 5,720,788 issued on Feb. 24, 1998 to Ronald R. Puckett et al., titled "Air Filter Element And Air Filter Assembly Employing The Filter Element," describes a generally cylindrical or truncated conical filter element and housing therefor. The air inlet to the housing is offset from the centerline of the filter element, thus causing air to spiral about the filter element to some extent prior to passing through the element. Larger debris particles are trapped at the base of the filter element, within the housing. The Puckett et al. filter element and housing have a considerably larger diameter than the engine air inlet to which they are secured, as is shown clearly in FIG. 2 of the Puckett et al. U.S. Patent, thereby making access difficult to any carburetor to which the assembly is secured.
U.S. Pat. No. 5,755,843 issued on May 26, 1998 to Tommy Sundquist, titled "Air Filter With Reusable Gable Plate," describes a filter and housing with the filter end plates (gables) being removable from the filter element, which is discarded after a period of use. The filter (and housing) is relatively bulky, with the filter and housing extending far beyond the dimensions of the carburetor or other air inlet to the engine, as is shown clearly in FIG. 1 of the Sundquist U.S. Patent. Moreover, as in the case of the Puckett et al. U.S. Patent described immediately above, no top or axial flow through a filter element and directly into the engine intake system (carburetor throat, etc.) is possible with the Sundquist filter apparatus, which straight, axial flow path is the only flow direction permitted by the present filtered cover.
U.S. Pat. No. D-151,464 issued on Oct. 19, 1948 to Niels H. F. Olsen, titled "Air Filter," illustrates a design apparently having two outlet passages therefrom, for a dual carburetor system. The overall dimensions of the filter and housing are considerably wider than the outlet passages which would connect to the carburetor throats. Moreover, it would appear that the Olsen filter design permits only generally radial flow, as the top of the design appears solid, thus precluding any axial flow therethrough.
U.S. Pat. No. D-157,443 issued on Feb. 21, 1950 to Joseph B. Sebok et al., titled "Combination Air Cleaner And Intake Silencer Unit," illustrates a device having an appearance generally like the conventional oil bath air cleaners used in automobiles of the 1930s and into the 1950s. The outlet for connecting to the engine intake system extends from the side of the lower portion of the device, with the lower and particularly the upper portions of the device having diameters considerably larger than the engine intake connecting portion. The Sebok et al. design could not be used with downdraft type carburetors, due to the lateral engine intake connector, and no axial flow is apparent through the top of the Sebok et al. air cleaner design.
U.S. Pat. No. D-178,812 issued on Sep. 18, 1956 to Joseph B. Sebok, titled "Air Cleaner And Intake Silencer Unit Or Similar Article," illustrates a design apparently having only a few small louvers disposed in one side, for intake air. The connection to any engine inlet system is apparently smaller than the housing, with no air passage being apparent through the top of the design.
U.S. Pat. No. D-213,403 issued on Feb. 25, 1969 to Alex Kraus, titled "Air Cleaner Cover," illustrates a generally flat, circular sheet of material having a series of grooves formed diametrically across the top thereof. The exemplary air cleaner illustrated with the cover design is a circular type, with air entering radially through the sides thereof. The Kraus air cleaner cover design appears to be solid, thus precluding any air passage therethrough, unlike the present filtered cover invention which allows air to pass through the top thereof.
U.S. Pat. No. D-293,796 issued on Jan. 19, 1988 to Neil F. Nagy, titled "Air Cleaner Cover," illustrates a generally round design apparently having a rough cast or similar finish across the upper surface thereof, and extending partially down the sides. It is not clear where the air inlet area of the design is located, but a series of what appear to be slots is located in the rough finished area at each side of the design. No top passage for air ingestion is apparent in the Nagy design.
U.S. Pat. No. D-295,444 issued on Apr. 26, 1988 to Tommy Sundqvist, titled "Cover For An Automotive Air Filter Housing," illustrates a design comprising a generally flat, circular plate with slightly raised circular areas thereon. The plate appears to be solid, with no means for allowing airflow through the plate, as opposed to the present filtered carburetor cover with its inlet passage formed in the top thereof.
U.S. Pat. No. D-399,944 issued on Oct. 20, 1998 to Gary R. Gillingham et al., titled "Conical Filter," illustrates a design having a generally cylindrical exterior, with a flange at one end and a series of raised concentric marks opposite the flanged end. The air inlet and outlet portions and inlet attachment means of the Gillingham et al. filter are not apparent from the drawings of their design patent.
Soviet Patent Publication No. 1,679,045 published on Sep. 23, 1991 describes (according to the English abstract) an electrostatic air cleaner having dual electrostatic elements. FIG. 2 indicates that all air to the filter passes through a single radially disposed inlet in the generally circular housing, with the top of the housing apparently being solid to preclude passage of air therethrough, unlike the present filtered carburetor cover. Moreover, FIG. 2 appears to indicate that all air flowing through the filter, passes into a relatively smaller passage which apparently represents the engine intake system. Thus, the air cleaner of the '045 Soviet Patent Publication appears to be considerably larger than the carburetor or other engine inlet component to which it is attached, whereas the present filtered cover has a diameter which is not significantly larger than the carburetor to which it is secured.
Japanese Patent Publication No. 4-269,365 published on Sep. 25, 1992 describes (according to the English abstract) an air filter and housing assembly in which the housing is configured to provide some additional flow by its shape, forming a "suction port." FIG. 2 of the drawings clearly shows an inlet passage extending from the air filter housing, with the engine intake connecting end of the inlet passage being considerably smaller than the size of the air box. It would appear that if the assembly were connected to a carburetor, that it would be necessary to remove the assembly in order to perform any adjustment or other work on the carburetor, due to the size of the air box assembly.
Soviet Patent Publication No. 1,772,392 published on Oct. 30, 1992 describes (according to the English abstract) an air cleaner having an impermeable housing which surrounds and encloses the filter element on the sides and top, with air being taken in through passages in the bottom, according to the drawing Figures. The filter element fits circumferentially tightly about an engine inlet passage, and is considerably larger than the passage. Such a configuration would preclude any access to a carburetor to which such a filter assembly would be secured, as the attachment completely surrounds the inlet system, rather than securing to the top or inlet face thereof, as in the present carburetor cover. Moreover, the assembly of the '392 Soviet Patent Publication does not provide for any air flow through the top of the housing, axially into the inlet system, as provided by the present filtered carburetor cover.
Russian Patent Publication No. 2,006,653 published on Jan. 30, 1994 describes (according to the English abstract) a filter element having progressively finer passages toward the interior thereof. The filter shape is not apparent from the drawing Figure illustrating the filter element itself, and no housing or means of connecting the device to a carburetor or engine inlet is shown.
Finally, French Patent Publication No. 2,701,656 published on Aug. 26, 1994 describes (according to the English abstract) a filter housing adapted for accepting filters having either axial or radial seals. The housing is a generally cylindrical container having sides, bottom, and top which are completely closed and sealed, with the exception of a single radially disposed inlet and a single axial outlet extending from the bottom thereof to the engine inlet system. No means is apparent for ingesting air through the top of the housing, whereas the present filtered carburetor cover draws all air through a filter disposed in the top of the device. Also, the filter housing of the '656 French Patent Publication has a considerably larger diameter than the engine inlet or carburetor to which the device is attached, thereby making it difficult or impossible to access the carburetor with the filter attached. Also, as in the case of nearly every other filter of the prior art, the filter element of the '656 French Patent Publication is relatively large and bulky, unlike the thin, planar filter of the present invention.
None of the above inventions and patents, either singly or in combination, is seen to describe the instant invention as claimed.